Method of forming stencil-sheets.



H. P. QEL'LIOTT.

METHOD OF FORMING STENCIL SHEETS. APPLICATlON FILED JULY 17. 1912.

1,136,591, Patented Apr. 20, 1915.

HARMON P. ELLIOTT, OF CAMBRIDGE, MASSACHUSETTS.

METHOD OF FORMING STENCIL-SHEETS.

Specification of Letters Iatent.

Patented Apr. 20, 1915.

Application filed July 17, 1912. Serial No. 709,871.

To all whom it may concern Be it known that I, HAaMpN P. ELLIOTT, a citizen of the United States, residing at Cambridge, in the county of Middlesex and State of Massachusetts, have invented an Improvement in Methods of Forming Stencil-Sheets, of which the following is a. specification.

Heretofore it has been the common practice to impress characters on mimeographpaper or paper having the general characteristics of mimeograph-paper, and herein termed a stencil-sheet, by means of typekeys of a typewriting machine of suitable description, and to subsequently use the same with the characters impressed thereon as a stencil. The impressed characters on mimeograph-paper are not easily discernlblt; even when holding the paper up to the li t.

This invention has for its object the production of a method of impressing characters on a stencil-sheet of ,mimeographpaper and the like and at the same time making the impressions easily discernible.

The new method consists in impressing characters on the stencil-sheet, against a carbon surface of equivalent surface, whereby carbon or other suitable material is deposited upon the back side of the sheet, in the same form as the characters im ressed in the front side thereof, so that t e impressed characters become opaque, the back of the impressed characters being blackened or deeply colored, thus making them easily discernible. I

My invention is of special importance in connection with address-plates involving the employment of mimeograph paper and the like as a stencil-blank, for, in such case, the addresses which are impressed on the mimeograph-paper are readily discernible, enabling them to be easily read.

Figure 1 represents in perspective view a portion of a typewriting machine, an address-plate having a stencil-sheet or blank of mimeograph-paper and apiece of carbonpaper, all arranged for carrying out my invention. Fig. 2 is an enlarged sectional view of a portion of the stencil-sheet having a character impressed on one side of it and a substance deposited on the back side of it opposite the impressed character to render the character opaque.

10 represents an address-plate havmg mimeograph-paper 12, as a stencil-sheet or blank, such, for instance, as shown in my Patent No. 1,068,578, dated July 29, 1913, yet it will be understood that this form of address-plate is here shown merely as one of the numerous ways of using my invention.

14 represents the platen, and 15 one of the type-keys of a type-Writing machine which may be employed to impress characters on the stencil-sheet 12.

16 represents a sheet of carbon-paper which is arranged on the platen contiguous the stencil-sheet 12, with its carbon surface in contact with the back side of said sheet,

and by means of the type-keys 15 characters are impressed upon the front side of the stencil-sheet against the sheet of carbon paper, whereupon the same characters are printed on the back side of the stencil-sheet opposite the characters which are impressed on the front side thereof, so that the characters thus impressed are rendered opaque, being deeply blackened by the carbon which is deposited on the stencil-sheet, and the contrast between the opaque o'r deeply blackened characters and the remaining portion of the stencil-sheet enables the impressed characters to be easily read. The carbonpaper also serves as a cushion at the back side of the mimeograph-paper.

I find that blackening the back side of the stencil-sheet opposite the characters impressed on the front side thereof does not affect the subsequent use of the stencil-sheet, as the ink employed passes freely through the stencil-sheet substantially the same as if the carbon was not applied thereto.

I claim c The method of forming a stencil consisting in placing a sheet carrying a transfer medium upon the rear face of a stencil sheet, and thereupon impressing the front face of said stencil sheet with the desired characters, whereby said characters are simultaneously outlined and rendered opaque on the stencil sheet b said transfer medium.

- In testimony w ereof, I have signed my name to this specification, in the presence of two subscr bing witnesses.

HARMON P. ELLIOTT. 

